@mixin rect($width, $height) {
  width: $width;
  height: $height;
}

@mixin box($width, $height, $bdrs: 0px, $bg-color: #fff) {
  @include rect($width, $height);
  background-color: $bg-color;
  border-radius: $bdrs;
}

@mixin square($edge, $bdrs: 0, $bg-color: #fff) {
  @include box($edge, $edge, $bdrs, $bg-color);
}

@mixin circle($diameter, $bg-color: #fff) {
  @include square($diameter, 50%, $bg-color);
}
